Two axially-laminated Glued Axially-Laminated Synchronous Reluctance Permanent Magnetic (SR-PM) motors are designed and tested. Compared to general Axially-Laminated Synchronous Reluctance (SR) motors, the steel brack...
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Computer control and monitoring system (CCMS) is quite important for high power converters (HPCs) operation. This paper presents a novel CCMS, which integrates a database management system (DBMS) into the monitoring s...
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ISBN:
(纸本)7506274078
Computer control and monitoring system (CCMS) is quite important for high power converters (HPCs) operation. This paper presents a novel CCMS, which integrates a database management system (DBMS) into the monitoring software to get the beneficial features such as simple configuration and compact structure. In its communication system, an advanced optical fiber communication (OFC) technology is applied and priority-based communications is proposed to improve the reliability and the real time of the communications. Furthermore, a friendly standard Windows human-machine interface (HMI) is provided. The reliability and performance of the system are verified by system tests and practical operations.
To research the influence of multi-phase winding to generators and calculate the losses in solid rotors, the stator mint of a 12-phase asynchronous generator have been well analyzed and finite element method by ANSYS ...
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ISBN:
(纸本)7506274078
To research the influence of multi-phase winding to generators and calculate the losses in solid rotors, the stator mint of a 12-phase asynchronous generator have been well analyzed and finite element method by ANSYS software has been applied to get the accurate losses in the rotor through both harmonic and transient 2-D analysis. The relationship between stator harmonic current and stator harmonic mint has been deduced and proved through ANSYS software to some extent, and rotor losses produced by both stator fundamental current and stator total current have also been obtained and compared. The results show that 12-phase stator winding with appropriate short pitch can effectively eliminate or reduce many mmf produced by stator fundamental and harmonic current and rotor losses are mainly produced by stator fundamental current.
In view of the impossibility of current measurement in actual grounding plane in power electronic equipment, an equivalent circuit model is set up in this paper using the partial element equivalent circuit (PEEC) meth...
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ISBN:
(纸本)7506274078
In view of the impossibility of current measurement in actual grounding plane in power electronic equipment, an equivalent circuit model is set up in this paper using the partial element equivalent circuit (PEEC) method to simulate and calculate current distribution in grounding plane. The inductance parameters calculated are fairly coincident with experiment results, and some conclusions of current distribution are summarized. It is shown that the equivalent circuit model using PEEC method presented in this paper is a feasible and promising way to model and calculate current distribution in grounding plane.
HVDC Light is more and more concerned recently to improve power system stability due to controllability of its IGBT valve. In this paper, a model of HVDC Light system will be established and analyzed. And a nonlinear ...
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The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (L...
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The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (LSE) method. But the LSE method is unstable in practical applications. A popular way to overcome instability is the Tikhonov regularization. However, difficulties will encounter when adjusting the so-called regularization parameter a. Moreover, how to truncate the iteration at appropriate steps is also challenging. In this paper we use the trust region method to deal with the image restoration problem, meanwhile, the trust region subproblem is solved by the truncated Lanczos method and the preconditioned truncated Lanczos method. We also develop a fast algorithm for evaluating the Kronecker matrix-vector product when the matrix is banded. The trust region method is very stable and robust, and it has the nice property of updating the trust region automatically. This releases us from tedious finding the regularization parameters and truncation levels. Some numerical tests on remotely sensed images are given to show that the trust region method is promising.
This paper presents an accurate flux observer used in distributed multi-processor (DMP) adjustable speed drive systems. The stator flux linkage is estimated with a full-order observer, while the rotor speed is identif...
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ISBN:
(纸本)7506274078
This paper presents an accurate flux observer used in distributed multi-processor (DMP) adjustable speed drive systems. The stator flux linkage is estimated with a full-order observer, while the rotor speed is identified by using Lyapunov theorem. In order to improve the system performance in a wide speed range, the stator resistance is estimated simultaneously. In this paper, the structure of the DMP system, the principle of the full-order observer and the method for identifying the rotor speed and state resistance are all described in details. Relevant simulation results based on MATLAB/SIMULINK are given to prove the performance of the method. Experiments of a real system also verify the feasibility of this scheme.
A set of generalized symmetries with arbitrary functions of t for the Konopelchenko-Dubrovsky (KD)equation in 2+1 space dimensions is given by using a direct method called formal function series method presented by Lo...
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A set of generalized symmetries with arbitrary functions of t for the Konopelchenko-Dubrovsky (KD)equation in 2+1 space dimensions is given by using a direct method called formal function series method presented by Lou. These symmetries constitute an infinite-dimensional generalized w∞ algebra.
The permanent magnet assisted synchronous reluctance (SR-PM) machine can not only offer higher torque capacity and improved power factors compared with the conventional synchronous reluctance machine, but also own wid...
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The permanent magnet assisted synchronous reluctance (SR-PM) machine can not only offer higher torque capacity and improved power factors compared with the conventional synchronous reluctance machine, but also own wider adjustable speed range compared with the permanent magnet machine. This paper presents a new method to optimize the key parameters of the machine under keeping the torque of the machine as large as possible by controlling the stator current. Nonlinear optimization and functional analysis are used to obtain the maximal torque at a certain speed. The investigation of many groups of the parameter data shows that the performance of a machine is influenced by various factors such as magnetic materials, the quantities of the material in the rotor, the turns of windings in the stator and so on. The best one should be chosen for applications. The trend of all the curves verifies the simulation results.
In the medium voltage adjustable speed drive (MV-ASD) systems, low switching frequency results in high harmonics in the output voltage waveform, which is harmful to the isolation of the induction motor. Therefore, the...
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In the medium voltage adjustable speed drive (MV-ASD) systems, low switching frequency results in high harmonics in the output voltage waveform, which is harmful to the isolation of the induction motor. Therefore, the power filter is usually set between inverter and motor. However, self-excitation oscillation easily occurs under this structure due to the filter capacitor, which could continuously bring up the DC-link voltage of the inverter, and even destroy the devices in inverters. One of the effective ways to eliminate the self-excitation oscillation is to set the inverter to three-phase short-circuit braking state, which is described and analyzed in detail in this paper. Three-phase short-circuit braking could be easily realized in the inverter-motor system. It can be verified by both simulation based on PSIM and test results that this is an efficient way in real applications. Finally, the characteristics of the short-circuit braking is summarized and beneficial suggestions on using this braking method are presented
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